Analytical Chemistry

Figure 4.19 Thermal conductivity detector (TCD). balance signal in the bridge circuit. The imbalance is registered as a deflecti ...

Figure 4.20 Flame ionization detector (FID). Nitrogen/Phosphorus Detector This is a more recent introduction which is (NPD), bas ...

the bead is not electrically heated the response is the same as a conventional FID. The detector is thus a three-in-one device w ...

is sensitive to temperature changes. The carrier gas must be exceptionally pure as oxygen, air and water at levels exceeding abo ...

Specialized Techniques Used in Gas Chromatography Temperature Programming The effect of column temperature on chromatographic re ...

Figure 4.23 (a) Isothermal separation of homologous series of alkanes at 150°C. Column 3% Apiezon-L on 100–120 mesh VarAport 30. ...

Figure 4.24 Capillary column separation of some constituents of human urine. ...

a few milligrams of the sample in the injection port of the chromatograph, the volatile products then being swept onto the colum ...

Figure 4.25 Headspace sample injection system (positioned in a heated oven). Comparison of Retention Times Provided that operati ...

Figure 4.26 Measurement of adjusted retention time, t'R. The value of αx is then compared with published values of known compoun ...

Figure 4.27 Graph of log adjusted retention times of n-alkanes versus carbon number. The open circles show log retention times o ...

the width at half height or by calculating the area of a triangle formed by the baseline and the sides of the peak produced to i ...

The formula assumes that the detector sensitivity is the same for each component. If this is not the case, the response of each ...

Figure 4.29 (a) GC-spectrometer system. (b) Jet-orifice separator for packed column GC-MS. (c) Direct insertion of capillary col ...

across the gap and on into the mass spectrometer whereas the lighter helium atoms are deflected outwards by the vacuum and are p ...

computerized data processing system is essential. Quantitative analysis can be accomplished by monitoring standards and samples ...

Applications of Gas Chromatography Along with high performance liquid chromatography, gas chromatography is the most widely used ...

performance is largely due to very slow mass transfer between stationary and mobile phases and poor packing characteristics lead ...

(1)— Solvent Delivery Systems These include solvent reservoirs and inlet filters, solvent degassing facilities and one or more p ...

the screw-driven syringe and the hydraulic amplifier. The former consists of a variable-speed stepper motor which drives a plung ...